1 Biogas Sanitation Systems Heinz-Peter MANG & Ina Patricia JURGA Institute of Energy and...

1

Biogas Sanitation Systems

Heinz-Peter MANG & Ina Patricia JURGA

Institute of Energy and Environmental Protection (IEEP)

Chinese Academy of Agricultural Engineering (CAAE)

E-mail: [email protected]

International Conference on

2农业部规划设计研究院能源环保 - 农业部能源与环境技术开发中心Institute of Energy and Environmental Protection (IEEP)

Center for Energy and Environmental Protection Technology Development (CEEPTD/MOA)



Basic ideas of Ecological Home and Prosperity Program

Basic ProjectBasic Project

PPRROOGGRRAAMM

Improved stove, energy saving “Kang”

Biogas digester

Northern “Four-in-one”Northern “Four-in-one”

Solar cooker, water heater, heating house

Wind power, Photovoltaic, micro hydro

Road, water supply infra. reconstruction

Southern “Pig-biogas-fruit”Southern “Pig-biogas-fruit”

Northwest “Five-Matches”Northwest “Five-Matches”

Biogas digester,animal-pen, kitchen, toilet reconstructions

Core ProjectCore Project

Extension ProjectProject



All organic materials can ferment or be digested:

faeces from cattle, pigs and possibly from poultry and humans, organic waste, energy crops, and organically loaded wastewater.



If the daily amount of available dung (fresh weight) is known, gas production per day will approximately correspond to the following average values:

1 kg cattle dung 40 litre biogas

1 kg buffalo dung 30 litre biogas

1 kg pig dung 60 litre biogas

1 kg chicken droppings 70 litre biogas

1 kg human excrements 60 litres biogas

If the live weight of all animals whose dung is put into the biogas plant is known, the daily gas production will correspond approximately to the following values:

cattle, buffalo and chicken: 1,5 litres biogas per day per 1 kg live weight

Biogas potential

Diets higher in protein and lower in fibre, resulting in higher biogas production values!!!

The maximum of biogas production from a given amount of raw material depends on the type of

substrate. As more biogas per unit

produced, as better the BOD reduction.



biogas as energy

1 m3 Biogas (approx. 6 kWh/m3) is equivalent to:

Diesel, Kerosene (approx. 12 kWh/kg) 0.5 kg

Wood (approx. 4.5 kWh/kg) 1.3 kg

Cow dung (approx. 5 kWh/kg dry matter) 1.2 kg

Plant residues (approx. 4.5 kWh/kg d.m.) 1.3 kg

Hard coal (approx. 8.5 kWh/kg) 0.7 kg

City gas (approx. 5.3 kWh/m3) 1.1 m3

Propane (approx. 25 kWh/m3) 0.24 m3

Amount cooked Time (min)

Gas(L)

1 L water 10 40

5 L water 35 165

500 g rice 30 140

1000 g rice 37 175

350 g pulses 60 270

700 g pulses 70 315

Equipment Amount of biogas

Household burners 200 – 450 L/h

Industrial burners 1000 – 3000 L/h

Refrigerator 100 L depending on outside temperature

30 – 75 L/h

Gas lamp, equiv. to 60 W bulb 120 – 150 L/h

Biogas/biodiesel engine per bhp 420 L/h

Generation 1kwh electricity biogas/biodiesel or gas engines

500-700 L/h

Sasse, India, 1988



Options for biogas utilisation



Biogas as fuel for waste incineration

Waste incineration needs fossil fuel to burn waste in a rotating kiln; this could be partially replaced by biogas



Electricity from CHP-engines

Gas-engine electricity generation needs medium-grade biogas purification (removal of moisture and trace gases)



Biogas feed in the natural gas grid

Biogas needs to be high-graded with carbon-dioxide removal to natural gas standards.



Biogas as fuel for vehicles

This option needs high-upgraded biogas with a quality compared to LNG/CNG



For biogas plant regarded from an energy point of view, its better to have some animal manure or additional feed of organic waste, and to optimize the retention time related to energy output ./. construction volume.For biogas as a sanitation option it is more important to look for the sanitization of the incoming black-, brown-, or wastewater and organic wastes. Therefore the input material stays longer in the digester, and the retention time will be adopted with an optimum of sanitation degree and biogas production.

Biogas sanitationHuman excreta from dry or low flush toilets and biodegradable organic fraction of household waste could enter a (on-site or off-site) anaerobic (wet or dry) digester to be treated and to produce biogas.



Under plug flow conditions - without post-treatment in wetlands or polishing ponds - the usual treatment of faecal sludge, properly applied by

Retention time

1.anaerobic psyrophilic fermentation (above 10°C and retention times of at least 100 days),

2.mesophile digestion (above 30°C with retention times of at least 50 days) or

3.thermophile digestion temperature (above 55°C and about 10 days retention time),

can be considered as sufficient. (volume ratio: 10:5:1)



The concentration of nitrogen in the black water cold be so high, that the digestion process could be stopped. Ammonia from the urine will be transformed by enzymes in urea, carbon dioxide and ammoniac. Urea will be toxic to the bacteria (self-intoxification).

This could be solved by solid/liquid separation (AQUATRON, filter bag, settler) or urine diversion toilet bowls and pans, and the “solid” part (faeces, sludge) are digested.

Biogas from brown water



III. Benefits Achievable

a) Social benefits

b) Economic benefits

c) Environment and ecological



a) Social Benefits

Job creation for local peopleHealth improvement—disease reduction

due to utilization of clean energy and end products use as land fertilizer

Especially good for womenLifestyle improvement



Dispose of your waste water and save money doing it!SRC upbeat about biodigester septic tank technology

By Petre Williams Observer staff reporterSunday, May 02, 2004

In the 1970s when the Germans introduced biodigester septic tank (BST) technology - a money- saving way to solve the acute waste water disposal practices in Jamaica - it was an idea whose time had not yet come.Three decades later, the state-run Scientific Research Council (SRC) is getting ready to embark on an aggressive promotion of its biodigester septic tank system, hoping to cash in on the many spin-off benefits. SRC executive director, Dr Audia Barnett, is enthusiastic about the technology: "You are treating your waste water. You are getting gas, which you can use for cooking. You are getting water you can use for irrigation and you are getting literally no waste," she told the Sunday Observer.

"There's practically no (need for) maintenance. It's a system that my staff likes to call 'set it and forget it'. It's not like the septic tank that you have to be pumping every now and again," Barnett said.The SRC is reporting that there has been renewed interest in BSTs, as they are called. "We have seen a resurgence... of interest in our BSTs, both at the residential level and at the industrial level," said Barnett.



b)Economic Benefits—energy saving

Biogas lamp



Biofuels and conversion

% dry matter Gas prod. Combust.Manure 7 - 12 + + + -Black (brown) water 0.5 - 2 + - - -

Sludge 25 - 50 + + + / -

Slaughter waste 40 - 60 + + + + + + / - -Wet organic waste 20 - 50 + / - + / -

Energy in brown water per person per year75 – 200 kWh net, biogas energy output

GTZ, 1997 and NLH, 2003

Diets higher in protein and lower in fibre, resulting in higher biogas production values!!!


Center for Energy and Environmental Protection Technology Development (CEEPTD/MOA)改厨改厨

Avoid indoor Avoid indoor air pollutionair pollution



Anaerobic sanitization (BRTC, China 1985)



1,00E+00

1,00E+01

1,00E+02

1,00E+03

1,00E+04

1,00E+05

1,00E+06

1,00E+07

1,00E+08

1,00E+09

GKZ EBA GCF FCF FKS

Keimart

Anz

ahl i

n K

BE

/ g

Rohgülle

Biogasgülle

93,75%

99,90%

Anlage: Laukenmann Temp.: 38°C VWZ.: 80 Tage Typ: Betonfermenter Datum: Juni 1993

99,98%

99,70%

Messung durch Institut für

Tierhygiene, Universität Hohenheim

99,98%

Reduction of pathogens



Geruchsminderung in Abhängigkeit von der Verweilzeit

0

50

100

150

200

250

10 12 15 40

Verweilzeit in Tagen

rela

tive K

on

zen

trati

on

in

Pro

zen

t x

p-Kresol

Ethyl-Phenol

Indol

Skatol

Iso-Buttersäure

Smell reduction through digestion



b) Economic Benefits

Energy savingFarm developmentVarious use of end product

27

Model Pure benefit yearly

(unit: yuan)

Household biogas 600

Northern “four-in-one” 3000

Southern“pig-biogas-fruit” 2000

b) Economic benefits---income increase



Livestock

Biodigestor

Pond

Crops, trees, shrubs

ManureEffluent

IrrigationFeed

Family

BiogasExcreta

The ecological farm



Pig-pen improvement

31

3.5mu forest3.5mu forest8 m8 m

One biogas digesterOne biogas digester

33

c) Environmental and ecological— protect forest



The use of biomass as a substitute for fossil fuel represents a high potential for the avoidance of GHG emissions.

One opportunity is associated with the processing of faeces or brown water, by which means biogas is obtained. The latter produces energy and at the same time reduces tradable methane emissions1.

Fossil energy substitution

1) The Clean Development Mechanism (CDM) is a compensation mechanism. It allows industrial countries to obtain emission reduction credits with emission reduction projects in developing countries. The credits are called Certified Emission Reductions (CER). An Annex I country invests in a Non-Annex I Country and cooperates with private or public institutions. The accounting of such reduction credits starts retroactively from the year 2000 onward.



Environmental benefits---CO2 and CH4 reduction

2.42%2.43%

81.93%

13.22%

i mproved stoveenergy-savi ng kanghousehol d bi ogasother

CO2

CH4

1, 9%

29.3%4.9%

63.8%

0.2%

省柴灶节能炕户用沼气大中型沼气工程其它

CH4



1.Composting of feaces and biowaste is ambivalent. Composting (aerobic storage) of feaces can reduce CH4

emissions but will increase N2O by a factor of 10. In CO2 equivalents there is no change.

2.Composting is not recommended as a Climate Emission Gas mitigation option (Bates 2001)1.

3.Controlled anaerobic digestion of feaces, manure and biowaste combined with biogas production is a most promising option for GHG mitigation (Jarvis & Pain 1994)2.

1) Bates J (2001): Economic Evaluation of Emission Reductions of Nitrous Oxides and Methane in Agriculture in the EU. Contribution to a Study for DG Environment, European Commission by Ecosys Energy and Environment, AEA Technology Environment and National Technical University of Athens.

2) Jarvis SC and Pain BF (1994): Gaseous emissions from an intensive dairy farming system. Proceedings of the IPCC AFOS Workshop. 55-59. Canberra, Australia.

No GHG mitigation by composting!



Biogas for overall household sanitation

• decentralised treatment of household wastewater with or without agricultural and organic household , kitchen waste

valuable nitrogen remains available energy

fertilizer



Baffled septic tank

137,000 community biogas septic tanks (DEWATS) for purification of household wastewater with more than 0.5 billion tons of wastewater treated annually.



Technical Concept

Biogas tank

Sludge stabilization and separation tank Oct. 2005 Andreas Schmidt



Sketch of biodigester replacing a septic tank. Wastewater as well as kitchen and garden waste enter the digester and are broken down to biogas and fertile water.

The advantages: No more emptying of septic tank. Reuse of all water in the garden. Less cost on cooking energy.

Methane producing organisms produce gas

Other organic feeding material, dry toilet.

Gas taken to the house

Water flowing into the expansion canal, also constructed/combined as fixed film filter

Root Treatment System

Storage for irrigation water – H20 could be pumped or irrigate gravitationally

Irrigation by gravity

Components together

Brown-, black-, grey-water connected



Running cost (-) or benefits (+) in Maluti per year (4 person household)

Conventional septic tank - 600 Biodigester septic tank +400 Cheap pit latrine - 50 Sophisticated double vault VIP latrines - 100 Ecosan toilet with urine separation,

utilizing compost and urine +200 Minimum urine separation set up,

utilizing urine only + 30

40

Loop

Biogas Sanitation Systems

Heinz-Peter Mang

Chinese Academy of Agricultural

Engineering Beijing

1 Biogas Sanitation Systems Heinz-Peter MANG & Ina Patricia JURGA Institute of Energy and...

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